/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.explorer.ui.management.identity;

import com.vaadin.data.Item;
import com.vaadin.data.util.ObjectProperty;
import com.vaadin.data.util.PropertysetItem;
import org.activiti.engine.IdentityService;
import org.activiti.engine.identity.Group;
import org.activiti.explorer.data.AbstractLazyLoadingQuery;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;


/**
 * Query that selects available groups for a user.
 *
 * @author Joram Barrez
 */
public class GroupSelectionQuery extends AbstractLazyLoadingQuery {

    protected transient IdentityService identityService;
    protected String userId;

    public GroupSelectionQuery(IdentityService identityService, String userId) {
        this.identityService = identityService;
        this.userId = userId;
    }

    public int size() {
        return (int) (identityService.createGroupQuery().count()
                - identityService.createGroupQuery().groupMember(userId).count());
    }

    public List<Item> loadItems(int start, int count) {
        List<Item> groupItems = new ArrayList<Item>();
        Set<String> currentGroups = getCurrentGroups();

        int nrFound = 0;
        int tries = 0;
        while (nrFound < count && tries < 5) { // must stop at some point in time, as otherwise size() would be reached

            List<Group> groups = identityService.createGroupQuery()
                    .orderByGroupType().asc()
                    .orderByGroupId().asc()
                    .orderByGroupName().asc()
                    .listPage(start + (tries * count), count);

            for (Group group : groups) {
                if (!currentGroups.contains(group.getId())) {
                    nrFound++;
                    groupItems.add(new GroupSelectionItem(group));
                }
            }

            tries++;
        }

        return groupItems;
    }

    protected Set<String> getCurrentGroups() {
        Set<String> groupIds = new HashSet<String>();
        List<Group> currentGroups = identityService.createGroupQuery().groupMember(userId).list();
        for (Group group : currentGroups) {
            groupIds.add(group.getId());
        }
        return groupIds;
    }

    public Item loadSingleResult(String id) {
        throw new UnsupportedOperationException();
    }

    public void setSorting(Object[] propertyIds, boolean[] ascending) {
        throw new UnsupportedOperationException();
    }

    class GroupSelectionItem extends PropertysetItem {

        private static final long serialVersionUID = 1L;

        public GroupSelectionItem(Group group) {
            addItemProperty("id", new ObjectProperty<String>(group.getId(), String.class));
            if (group.getName() != null) {
                addItemProperty("name", new ObjectProperty<String>(group.getName(), String.class));
            }
            if (group.getType() != null) {
                addItemProperty("type", new ObjectProperty<String>(group.getType(), String.class));
            }
        }

    }

}
